Diaphragm pump



Oct. 11, 1938. A.- L. MENNEssoN 2,133,207

' DIAPHRGM PUMP Filed May 5, 1,937

Patented Oct. 11,1938

UNITED STATES Pari-:1511ioi-#Fics DIAPHRAGM PUMP Andr Louis France Mennesson, France, assignor to Socit Anonyme Solex, Neuilly-sur-Seine, (Seine) France, a society of Neuilly-sur- Seine,

Application May 5, 1937, Serial No. 140,992

' In France May 12, 1936 4 Claims.

invention comprise two diaphragms, connected4 between themselves, one of which serves for the 1.0 suction and delivery of the fluid and the other of which is actuated by the forces to eiect the drive, such as the variable pressure of a fluid,

determining the operation of the pump, the use of the doublediaphragm moreover avoiding danthe'engine mechanism.

The invention further consists, apart from this general arrangement, in certain other arrange-v ments which are preferably utilized at the same time, and more especiallyrelative to the case where the pump is used for the supply of a c arburettor and operates under the action o f the suction existing downstream of the throttlingl member thereof, and consists in making the space existing between the two diaphragms always Communicate -with the atmosphere, particularlywith the air-admission. conduit of thecarburettor. In'order that the invention may be better unto the accompanying drawing, in which:

Fig. 1 shows, in diagrammatic vertical section, a carburettor provided with a diaphragm pump constructed according tol the invention, the parts body I, the upper part vof which constitutes an air inlet 2 and the lower part of which is intended to be mounted on the induction pipe of the engine, a throttling member `3, a jet device l, supplied by a passage 5 from a constant level chamber 6 and delivering fuel into a venturi 1.

The carburetor is provided with a so-called "accelerating" diaphragm pump intended to in.- troduceja quantity of yadditional fuel at any point of the admission ofthe engine and which ger of leakage of the ud to be delivered towards derstood it will now be described with reference of the pump occupying a position corresponding .acts on its surface. When the throttling memis added tothe normal quantity of air-fuel mixture when the throttling member 3 is opened after having been closed, for example for slowrunning or for a change of speed.

For this purpose there are accommodated in 5 `a casing 8, which can be `mounted laterally on the body I of the carburetor, two diaphragms 9 and III separated by a space I3 and which are connected between themselves at *their middle part for example by a disc or rod II. In this way 10 the diaphragms divide ,thefcasing 8 into three -distinct chambers I2, I3,and I4.

The chamber`i2 is connected byv a-conduit I5, with a non-return valve I6, to a chamber which always contains fuel, particularly to the constant -15 level chamber 6. Moreover, the. chamber I2 is made to communicate-with a delivery tube I8, with calibrated orifice 'I9 provided with va nonreturnvalve I1, and whichopens into the induction pipe I of the engine upstream of the throttling member 3, or even of the jet device 4. It is realized that by the movement/in one direc-- tion of the diaphragm 9 (Fig. 1) thereis rst obtained the drawing in of a certain quantity of fuel into the'chamber I2 and by its movement in the opposite direction (Fig. l) the delivery of this quantity of fuel into the induction pipe I .l

The intermediate chamber I3 is connected by a tube 2li to the atmosphere or to the air inlet The chamber Il, bounded-`30 of the carburettor. by the diaphragm I0, is made .to'communicate, by a tube 2|,v with the induction pipe I downstreamof the throttling member 3. Moreover, a return spring 22 is housed in the chamber I4.

When there is occasion to close the throttling member 3, the suction increases in the part ofl the induction pipe downstream of the member 3 and in consequence in the 4tube 2| 'and the chamber I I. The diaphragm IIIis consequently drawn in and leaves the position shown in Fig. 2 to occupy its extreme position (Fig. 1) by compressing the spring 22. The diaphragm Il drawsalong the diaphragm 9 which draws ina certain quantity of fuel as explained above. Advantage--y Y ously the wall of the casing 8 is given such a 45 shape that the diaphragm I0, under the eect of the suction, is adapted to be applied exactly on thesaidwall so that this diaphragm is not subjected to toogreat forces. when` the suction ber 3 is again opened (Fig. 2) the suction diminishes and the spring-22 forces back the assembly of the two diaphragms insuch a way that the fuel is delivered into the induction pipe I. There is advantageously mountedmn the' central part 55 of the diaphragm 9 a valve 23 which is adapted to close the inlet of the conduit I8 when the acceleration pump is not operating.

The operation of such a double diaphragm pump istherefore identical with that of an ordinary acceleration pump with a single diaphragm.v However, by having recourse to the arrangement according to the invention and for which one face only -'of the diaphragm 9 is in contact with the fuel in order to draw in and deliver this latter whilst its other face is constantly subjected to a determined pressure and for which one face only of the diaphragm I0 is actuated by the eiect of the suction Whilst its other face is constantly subjected to the abovementioned pressure, the following advantages are obtained:

a. If the diaphragm 9 becomes porous or perforated, the fuel which passes through it is collected in the intermediate chamber I3 without being able to penetrate into the chamber I4, which prevents any direct communication between the fuel and the source of suction.

b. The accidental or fortuitous presence of the fuel in the intermediate chamber I3 does not hinder the operation of the pump in any way and this fuel can easily De withdrawn by the dismounting of the cover of the casing, particularly when it is desired to replace the perforated diaphragm 9, or through a simple orifice pierced for this purpose in the wall of the chamber I8.

c. As the diaphragm 9 is only in contact with the fuel and the diaphragm I0 with the gaseous mixture contained by the induction pipe I, these diaphragms can be made in different materials which do not run the risk of being attacked or deteriorated by the fluids with which they are in contact.

It will be evident that although the invention has been particularly described in connectionv with a Carburettor, it is not limited to such use as it may be otherwise employed, for example as an ordinary feed or delivery pump.

The invention is not limited to the precise forms or details of construction described, as these may be varied to suit particular cases.

What I claim is:-

1. In a carburetor having an air passage and a throttle valve therein, an accelerating pump com prising two spaced diaphragms, means at the peripheries of said diaphragms to exclude fuel from the space therebetween, means rigidly connecting the central portions of said diaphragms, housings cooperating with the exterior surfaces of said diaphragms to form two chambers, means for conducting fuel to one of said chambers, means for conducting fuel from said rst chamber to said air passage, means connecting the other chamber to the air passage on the downstream sideof the throttle valve, a spring in said second chamber acting on the outside of the diaphragm forming a part of the chamber, andmeans connecting the space between said diaphragms to a ANDR LOUIS MENNESSON. 

